The present invention relates generally to an article of footwear, and in particular to an article of footwear with adjustable cleats.
Articles of footwear with cleats have been previously proposed. Obeydani (U.S. Pat. No. 7,490,418) teaches footwear with manually extendable spikes. Obeydani teaches a gear assembly mounted within a heel portion. Threaded couplings are fixedly engaged with a sole portion and a plurality of spikes are each threadedly engaged with one of the threaded couplings.
Schaeffler (DE Patent Number 3644812) teaches a shoe heel with moveable spike nails. Schaeffler teaches a heelpiece with a reinforcement plate on which a nail plate rests. The nail plate includes spike nails, which project from openings in the heelpiece. A compression spring rests on the nail plate to urge the nail plate downwards. Schaeffler teaches that in some situations the spike nails are pressed back into the heelpiece interior. Schaeffler also teaches a screw that can be used to lock the nail plate at a height at which the spike tops are fixed above the exit height.
Sjosvard (U.S. Pat. No. 5,557,856) teaches an anti-skid device for footwear. Sjosvard teaches an anti-skid device with sliding members connected to spikes. An electric motor is configured to operate a gear mechanism to move the spikes between retracted and extended positions. Sjosvard also teaches sensing means and activating means for manually activating the electric motor.